Apparatus for wireless telegraphy.



No. 706,736. Patented Aug. 12, I902.

R. A. FESSENDEN.

APPARATUS FOR WIRELESS TELEGRAPHY.

(Application filed May 17, 1900. Renewed No v. 29, 1901.)

(No Model.) a Sheets- Sheet 7 Q R Q) m g Q 2 WITNESSES:

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No. 706,736. PatentedAug. l2, I902.

n. A. FESSENDEN. APPARATUS FOR WIBELESSTELEGRAPHY.

(Application filed may 17, 1900. Reziewed Nov. 29, 1901.

(No Model.) 3,Sheets$heet 2.

I I al suvs mron iQ J-d L AW -gwM w: mums PETERS co, PHOIID'UTHOV, WASHINGTON, 04 c7 No. 706,736. Patented Aug. 12, I902.

R. A. FESSENDEN.

APPARATUS FOR WIRELESS TELEGRAPHY.

(Application filed. May 17, 1900. Renewed Nov. 29, 1901.) (No Model.) 3 Sheets-Sheet 3.

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THE NOR-R15 Pcrzns 60.. PHOTO-LITNO wnsumsmu. n, c.

UNITED STATES PATENT OFFICE.

REGINALD A. FESSENDEN, OF ALLEGHENY, PENNSYLVANIA.

APPARATUS FOR WIRELESS TELEGRAPHY.

SI ECIFIOATION. forming part'ofLetters Patent No. 706,736, dated August 1%, 1902.

Original application filed-December 15, 1899, sorial'No. 740,429. Divided and this application filed May 1'7 1900. Renewed November 29, 1901- Sorial No. 845097- (No model.)

To all whom it may concern:

- Be it known that LREGINALD A. Fns'snw- DEN, acitizen of the United States, residing at Allegheny, in 'the county of Allegheny and State of Pennsylvania, have invented or discovered certain new and useful Improvements in Apparatus for Wireless Telegraph of which improvements the following is a'specification. I

The invention described herein relates to certain improvements in apparatus for the electrical transmission of signals from one station to another without the use of conduc tors connecting such stations, such apparatus being more especially designed for the carrying out of method described and claimed in applicatiou,Serial No. 740,429,'fi1ed December 15, 1899. I 1

In the methods heretofore employed the electromagnetic waves generated at the receiving-station produce voltages in the receiving-circuit. These voltages or en rreuts being impressed upon a suitable material normally non-conductive render the same conductive, and thereby permit the passage of a current through a circuit in which said material, usually'termed a coherer,is included. After the passage of the voltages produced by each seriesot' electromagnetic waves generated at the sending-station the coherer must be operated in some way to restore it to normal or non-conductive condition.

The object of the present inventir i, is to provide for the generation by currents produced byelectromagueticwaves of induced currents in a second element or circuit and by the reaction of the current in this second element or circuit on the field formed or produced by the currents in the receiving-couductor to produce motion which is directly or indirectly observable.

In general terms the invention consists in apparatus whereby the energy of electric currents produced by electromagnetic waves may he transformed into the energy of mo tion and the energy of such motion employed for producing intelligible signals.

The invention is hereinafter more fully described and claimed.

In the accompanying drawings, forming a part of this specification, Figure 1 isa diagrammatic view showing the arrangements ratus.

employed atdhe sen-ding and receiving stations. Figs. 2 and 3 are diagrammatic views illustrating a modification of the receiving apparatus. Fig. 4 is a side elevation of the apparatus shown in Fig. 3, and Fig. 5 is a further modification of the receiving appa- The apparatus employed at the sendingstation may be similar to that now in use for one extreme end 'to the other extreme end,

including all apparatus in series with the circuits, while the term radiating portion indicates all of sending-conductor from top orextreme end of same to point of junction .with the apparatus for effecting the oscillatory charging and discharging thereof, such as sparking terminals, transformercoils, armature,-. yvindings, doc. By electromagnetic waves as used herein is meant waves of a wave length long in comparison with the wave length of what are commonly called heat-wavesor .radiant heat. By grounded conductor is meant a couductorground ed either directly or through a'capacity, an inductance, or a resistance, so thatthe-cu'rrent in the conductor flows from the conductor to ground, and vice versa, when electromagnetic waves are generated. The terms tuned and resonant are used herein as one including the other. By the term current-operated wage-responsive device as used herein and by-me generally is meant wave-responsive devices having all their contacts good contacts and operated bycurrents ductor is conveiiiantly' formed by a wire or also includesa'generatorllzi and a recording wires 6, projecting up vertically or at an inclmatlon to a suitable height, which are alsov ;.:roun -Il'ed. A coil or coils 7 are arranged in the circuit of the'cond uctor 6, and an elementorcoil of wire 8, forming a closed circuit, s supported with a freedom of movement in such relation to the coil or coils 7..

that the current produced by the electromagnetic waves will induce a current in the element 8. The element 8 is suspended, p-r'ef 'erably, in such manner that a plane at rightangles to its axis will form an angle of approximately forty-five degrees (-5 'witha' plane at right angles to the axis of the coil or coils 7 so that the reaction of the current induced in said element,v with the field ,prn-

ducedb'y the coil or coils 7, will cause the element Sto move with reference to the coils 7.

.This motion ofthe element may be observable by means of a mirror 9, attached there- 'to, reflecting'a beain of light on a scale, or

said element may form a part of the circuit of a recording-siphon, &c. As shown in Fig. 2, the coil 7 may be connected to the secondary coil 11 of a transformer, whose primary coil 12 is connected in series with the receiv ing-conductor. A

A desirablejmeans for transforming the electromagnetic waves into-recordable motionis shown in Figs. 3 and 4. The element 8 is balancedon supporting-rods or knifeedges 13, one of which is formed of a good electrical conductor, as si-lver,-'the element 8 being preferably formed by a silverring. A carbon block 14 isso arranged that a' portion of the ring between the supporting-rods will normally rest lightly thereon. This micro phonic contact, the conducting pivotal sup port and the portion ofthe ring between them form parts of an electric circuit, which instrument 16, as a telegraphic sounder or the receiver ofa telephone. When a current is produced, as above described,'in the coil 7,

the element or ring 8 will be caused to press on the carbon block, thereby increasing its conductivity. When. 'using a telephone-receiver as a recording instrument, the gener- ""ator'15 is preferably of a character capable oi'xproducing an alternating current, as such current causes a constant vibration of .lhe

diaphragm, the vibrations increasing in intensity with an increased flowof current in the circuit.

the form shown in Fig. 1. In this it is sharply .diiferentiated from such ,devicesas the ooherer, which either givea strong indication or do not give any. This characteristic is advantageous in that if the signal sent-say a dotbe too weak to give an action of the full intensity it may still inmost cases be read and not missedentirely,'which is of value insending codednessages.

This increase in intensity of ac-", tion with increased flow of current is characteristic of this form of receiver and also of In'the construction shown in Fig.5 the cir-* I cu-it of the generator 15 is divided, one branch including a coil 16 and connected tofa micro;

Thesecontacts are arranged on opv:

tween the coils in equilibrium with relation 1 to the coils. Adjustable resistances may-be placed in the circuits of the coils, thereby avoiding the necessity of delicate adjustments of the carbon blocks. When the COllS and the ring or element 8 are energized, the pressure of..the latter on one contact is in- .creased and that on the other decreased,

thereby correspondingly changing the resistfiowof current through one coil and decreased flow through the other coil, due to the change 9O ment of the magnetic disk .17 than if only a in resistances; will produce a greater movesingle coil were used. The movement of the disk 17 can be rendered observable in many ways known .inthe electric signaling art-as,

for example, by securing a. mirror thereon.

, The closed circuit or element 8 is preferably made of a light good conducting material, such as alumiuiumor silver, so that it will quickly respond to changes in the current produced in the receiving-conductonby' electromagnetic waves. The ring or element 8 should have relatively low resistance and ances in the twobranches; Theincreased high self-induction, so that the cu rrent in the ring instead of being maximum at the instant whenthe current in the field-coil is .maximum is practically forty-five degrees different in phase from the current in the fieldcoil. To accom plish'this, the ring or element 8 may consist of more than one turn or coil of wire; but one'turn is preferable. preferred that the field should consist of a coil formed by a single turn of wire 7, as shown in Figs.- 2, 3, and 4, therebyreducing the resistance-drop in the receiving appara-.

tus, and hence increasing its ability "to resonate. By resistance is meant not onlypu re ohmic resistance, but also its well-known equivalent in alternating-current work-i. e.,-

losses produced by eddy-currents and hys--' 'teresis.

I Itwillbeunderstood thatinthe formsshown, inFigs. 3, 4., and 5 the coils 7, which-for convenience may be termed the field-coils, may be connected 'in series with the receiving-conductor, as shown in Fig. 1,.or may be connected to 1he secondary coils of a trans It is also;

former, the primary coil of which is connected in series with the receiving-conductor.

As shown in Fig. l, a condenser I9 may be connected in shunt with the field coil or coils 7 for the purpose of obtaining as large a current as possible inthe field-coil 7, as this increase in current will give a great torque to tl' cring R. The local circuit thus formed is coherer,

a closed circuit and is to be dilferentiated from the open local circuits employed in connection with the coherer. An alternatingcurrent circuit may be closed through a resistance, an inductance, or a capacity, and

since even the insulated ends ofa circuit will.

always have some capacity relative to each other it follows that all alternating-currentcircuits are theoretically closed. What is meant, therefore, by a closed alternating-current circuit is a circuit in which the current is relatively largefor a small impressed voltage in the circuit-i. e., the circuit is one of low virtull resistance as compared with a coherer. Byan unclosed or open I circuit is meant one in which the current is relatively small or negligible for a small impressed voltage-i. e., one whose virtual resistance is high. Where a current-actuated wave-responsive device is employed, a closed circuit should also be employed to obtain a large ef- 'fective current to actuate said device.

Where a voltage-actuated device, such as a is employed and alarge efiective dilierenceof potential is required, an open circuit, as defined above, should be used, This is especiallyimportant, because while a resonant rise of voltage may be obtained in an open circuit a large resonant rise of current is possible onlyin a closed circuit of low ohmic resistance used in-connection, with a source of maintained radiation. It will be evident that according to this definition of 4 closed andunclosed tuned circuitsin many cases the sending or receiving cond uctor would come under the head of a closed tuned circuit, especially when havinglarge capacityandlow inductance; but where reference is made herein to a closed tuned circuit a sending or receiving conductor is not meant.

When no condenser is employed, this largecurrent must flow in the vertical wire and therewould be a great loss of energy on ac-- count of the resistance of the receiving-conductor 6, and, further, without the condenser a large amount of energy will be required to give the statical charge to the receivin -con ductor. Hence on account of the small energy furnished by the waves a large current cannot be obtained in field coilor coils 7 withoutthecondenser. Byemployingacondeuser of the proper size relative to the received waves, so as to form a local circuit tuned to the periodicity of the electromagnetic waves, the current in receiving-conductor 6 may be made to have a value equal to dilference between the current in the field coil or coils and the current in the condenser. Either of these currents may therefore be large and either or both maybe used to produce motion, while the-current in' the receiving-conductor 6 may be kept so small that there is practically no loss of energy on account of its resistance or of the statical charging of the receiving-conductor and all the energy may be used in producing motion. Without the condenser the current in the field coil or coils 7 will be practage due to the capacity lead. When both the field-coil and the condenser are intro-- duced, one in'shunt with the other, there will be a current in the field coil or coils lagging ninety degrees.() and in the condenser acurrent leading ninety degrees, (90.) The sum of'the two currents, one hundred and eighty degrees apart in phase, is equal to the difference between their values. Hence-it there is a current in the field coil or coils of one ampere and in the condenser a current of nine-tenths of an ampere the current in the receiving-conductor 6 will be one-tenth of an ampere. By employinga similarlytuned local circuit in resonance to the periodicity used at the sending-station, said circuit consisting of a capacity in the form of a condenser and an inductance formed by-the connecting wires placed in shunt across the spark -gap, an increased efiect is also obtained on account of the oscillations being prolonged; 7

It is preferred to place a shunt-circuit containing a condenser across the terminals of the indnction-coilat the sendingstation for the purpose of maintaining sustained radia-' tion. This shunt-circuit must be tuned to the receiving-conductor; otherwise the oscillations preduced by it will have no action .upon .the wave-responsive device at the receiving-station.' This shunt-circuit by virtue of its capacity stores up an additional amount of energy, and when a spark passes across the gap, since the sending-conductor can radlate energy at a given rate, it must continue to radiate for a longer time in order to dissipate this additional stored-up energy.

It is characteristic of the method shown that the receiving mechanisms are actuated .by currents produced by electromagnetic waves and not by voltages, as in the case of the coherer. Hence when the receiving mechanisms described herein are used in connection with asecondary circuit said circuit 1s controlled by the currents generated by electromagnetic waves and not by voltages. It is also characteristic that when a secondary circuit is usedin connection with the type of wave-responsive device shown in Figs. 3, 4, and 5 that a portion of the secondary circuit is traversed and controlled by currents produced by electromagnetic waves. ther characteristic of my'improved system that the indications produced by the receiving mechanism herein described are dependent upon the total amount of energy omitted to form a signal, and. is not, as in the case of the coherer, dependent upon the maximum of the voltage. It is also characteristic of the combination of closed tuned circuits with current-operated waveresponsive devices that the etfect on the wave-responsive de-- It is fur- 15 eif'ect will be conserved, as in the case of the o generation of electromagnetic'waves, a re- 5 supported with its plane normally at anangle n'1otion, thecon'ibination of a receiving-con- 6 denser connected in shunt with said field,

5. 4. In a plant vice is cumulative i. (2., dependent on the total or integral activity of the circuit and not on theniaximum activity or voltage. On account of the fact that the period of electro- 5 magnetic waves, such as are commonly used in the art, is much less than that of practically producible and observable mechanical movementsasingle electromagnetic wave will have produced its impulses before the receiver IO herein described will have made an appreciable motion orhave been appreciably affected. Consequently if a source of sustained radiation be used .at the sending end each wave will produce its individual effect, and the ballisticgalvanometer the. eifects of all the waves will be added together and cumulative to produce an indication. Since in the arrangement herein described the receiver is 20 constantly receptive-i. a, is always capable of being affected by the waves-and not, as .in the case of the coherer, rendered incapable of response to the waves 'for"a portion of the time, the speed of signaling will be in- :5 creased. 4

I claim herein as my invention- 1: In a plant for the transmission of signals by electromagnetic waves,- the combination of means located at the sending-station for 30 the generation of electromagnetic waves, are-.

. ceiving-conductor at the other station,- means for directly translating the energy of the currents produced iii-the receiving-conductor by the electromagnetic waves into energy of mo- 5 tion' and-means for observing or recording suchmotion, substantially as set forth. 2. In a plantfor the transmission of signals. by electromagnetic waves, the combination of means located at the sending-station for the ceiving-conductor at the other station, a field coil or coils adapted to beenergized by the currents produced in the-,receiving-condactor and a ring forming a closed circuit movably less than a right angle to the field the ring having relatively low resistance and high selfv induction so that a current induced 'therein will impart a twisting movement to," the ring 50 and means for recording orobservingthe v movements of the ring, substantially as set forth I I 3. As a means for transforming the energy of'electromagnetic waves into the energy of ductor in which currents may be produced by electromagnetic'waves,'a field coil 01 '00llB adapted to be energized by the current produced in the receiving -conductor, a conand.-a ring forming a closed circuit movably supported in such relation to the field that a currentwill be induced'therein, substantially asset forth. g

' for the electrical transmission A: signals without the useo'f wiresfthe combination of means for the generation of elec-.

electromagnetic waves, a field formed by a single turn of wire adapted to be energized by the currents produced in the receiving-conductor, and a ring forming 'aclosed circuit movably supported in operative relation 0 the coil, the ring having relatively low re-' sistance and high self -induction, substantially as set forth.

.-6. In a system of transmission of energy by means of electromagnetic waves, a receiving system including in combination a receivingconductor and a wave-responsive device, the

portion of the receiving system containing said wave-responsive device constituting-a transmitter, substantially as set forth.

7. In 'a system of transmission of energy by electromagnetic waves, a receiving system including in combination a'receiving-cond actor, a wave responsive device, which'is also an inclosed circuit tuned to the frequency of the a l ductance and a condenser in'shunt thereto, said inductance and capacity being adjusted to make the portion of the receivingsystenr in which they are placed resonant to the freroc quency of the transmitter,substantially as set forth.

8. In a system'of transmission of energy by electromagneticwaves, a receiving system includingin combination a receiving-conductor and a wave-responsive device, the portion of the system containing. said wave-responsive device having two conducting-paths in sh unt' relation, one having ind uctanceand the other having capacity, said inductance and capaci'ty being adjusted to each other and to the frequency of the transmitter to cause one hundred and eighty degrees 'difierence in' phases of the currents in thetwo conductingpaths, substantially as set forth. 4

a 9,. In a receiving system for transmission of energy by electromagnetic waves, a closed circuit tunedfto the frequency of' the transmitted impulses and acu rrent-operated waveresponsive dev ice, substantially as setforth. 10. In a system of'transmission of energy by electromagnetic waves, a transmitter system includin a tuned cir.cuit',,said system bein'g adjust to radiate trainsof electromagnetjc waves in which a single ifrequencyis predominant, in combination with a receiver system includinga closed circuit tuned to said predominant? frequency, substantially as set forth.-

v I 3 I11. In-.a 'system of transmission ofener-gy by electromagnetic waves, a transmitter 5 11s..

tern including a closed tuned circuit, said system being adapted to radiate trains of electromagnetic waves inwhich a single frequency'is predominant, and a receiver system including "a closed circuit tuned to said predominant frequency, substantially as set forth.

12. In a system of transmission of energy 'by electromagnetic waves, the combination of a generator, a grounded sending-conductor, a receiving-conductor, means for translating the energy of currents produced at the receiving-station by electromagnetic waves radiated from the sending-conductorinto the energy of motion and means for observing or recording such motion, substantially as set forth.

13. In a system of transmission of signals 1 by electromagnetic waves, the combination receiving circuit of means for generating and radiating electrom'agnetic waves at the sending-station, a at the receiving-station tuned to the sending-circuit, and a low-resistance means forproducingsignals bycurrents produced by electromagnetic waves radiated from the sending-conductor, substantially as set forth.

1 '14. In a system of transmission of'signals by electromagnetic waves, the combination of means for generating and radiating electromagnetic waves at a sending-station, a rea ce ving-circult at the receiving-station tuned to the sending-circuit, and a current-actuated wave-responsive device included in said receiving-circuit, substantially as'set forth.

5. In a receiver system for signaling by electromagnetic waves, a low-resistance-receiving mechanism in series with a transformer, the primary of the transformer being in the circuit of the receiving-conductor, sub

stantially as set forth.

16. A system of signaling by electro'magnetic waves, having in combination a 'receiving-conductor and a differentially-Wound indicating mechanism controlled by currents produced in the receiving-conductor by electromagneticwaves, substantiallyas set forth.

17. 'Asystem of signaling by electromagnetic waves, having in combination a receiving -,conduc tor and a differentially-woundindicating mechanism dependent for its operation on currents produced by electromagnetic waves, substantially as set forth.

18. A system for-signaling by electromagnetic waves, having in combination therewith a dilferentially-wound mechanism dependent for its operation on currents produced by electromagnetic waves, substantially as set forth.

19. In a system of signaling by electromagnetic waves the combination of a receivingconductor, a secondary circuit and a currentactuated wave-responsive device controlling the secondary circuit, substantially as setr forth. 20. In asystem of signaling by electromagnetic waves the combination of a receivingconductor, a-secondary circuit and aself-re- SiOIll] g curren t-actuated wave-responsive device controlling the secondary circuit, substantially asset forth.

21; A system for signaling by electromagnetic waves having in combination therewith a currentactuated wave-responsive device 0perati've in a closed circuit, quency of the electromagnetic waves to which it is desired forth.

22. Ina plant for the transmission of electrical energy without the use of wires, the combination of means located at the sending-- station for the generation of electromagnetic waves, a receiving-conductor at the other station, and means having a low resistance for directly translating the energy of the currents produced in the receiving-conductor by the electromagnetic waves into the energy of motion, substantially asset forth.

23. In aplant for the transmission of electrical energy without the use of wires, the combination of means located at the sendingstation ior the generation of electromagnetic waves, and a low-resistance receiving mechanism at the other station operative by the currents generated by the electromagnetic waves, substantially as set forth.

24. In a plant for the transmission of electrical energy without the use of wires, the combination of means located at the sendingstation for the generation of electromagnetic waves, including a grounded sending-cond.nc-

tor, a receiving-conductor and a low-resist.- ance receiving mechanism in circuit wlththe receivingconductor, substantially as set forth.

25. In a plant for the transmission of electrical'energy without-theuse of wires, the

combination at the receiving-station of two tuned to the helocal or secondary circuits, a receiving mechanismhaving a. movable member, a wave-operated means adapted to increase the resist ance in onelocal circuit and to decrease the 'resistance in the otherilocal'oircuit, the currents thus modified tending to'pro'duce motion of the movable member in the same direction, substantially as set forth.

26. In a system of signaling by electromagnetic waves, the combination at thesendingstation of a generator, a sending-conductor, a spark-gap, and a condenser connected across the spark-gap so that the condenser and its connecting-wires form a local and parallel circuit in resonance to the sending-comluctor, substantially as set forth.

27. In a system of signaling by electromagnetic waves, the combination at the sendingstation of a generator, a grounded conductor,

a spark-gap, and acoudenserconnected across the spark-gap so that the condenser and its connecting-wires form a local and parallel circuit in resonance to the sending-conductor.

28. In a receiving system for transmission energy'of each wave to develop electric-cur quency of stantially as set forth.

of energy by electromagnetic waves, aclosedcir'cuitot low resistance tuned to the frew e transmitted impulses and a current-actuated wave-responsive -device, sub- 29. In a system of signaling by electromagnetic waves, the combination at the "receiv- Jug-station of a closed tuned circuit and a current-operated wave-responsive device adapted to give indications proportioned to phototal activity-ofthe receiving-circuitgs'ubstantially as set forth.

30. In a system of wireless transmission of energy by electromotive waves an apparatus for utilizing the energy of said waves, said apparatus including incombination a conductor constructed and arranged to cause the r-ent'flow, means for rendering said currentflow persistent andfor coordinating the currents developed by successive waves to cause Y them to act cumulatively upon each other to produce an increased or reinforced resultant current-flow, and means operated by said resultan-t current-flow to producefa sensible effect or'indication, substantially as set forth.

A system'of signaling by electromotive waves, having at the receiving-station acurtimed circuit.

waves, having in combination a current-operated, constantly-receptive wave-responsive device at the receiving-station and a source of persistent radiation at the sending-station.

35. A system ofsignaling by electromotive waves, having in combination a closed tuned tive, .wave-responsive-device at the receivingstation and af'source of persistentradiation at the sending-station.

In testimony whereof I have hereunto set my hand.

- REGINALD A. FESSENDEN. \V'i tn esses r WM. McK. Bimnonolis,

Amman H. 'lmnssns.

rent-operatedconstantly-receptive wave-re- 3 I 32. A system of signaling by electr'omotive 34. A system of signaling by electromotive circuit, a current-operated, constantly-recepsponsivo device, in conbination with a closed 

